Here is a small bit of refining the handling of a Card to Wallet routine, with the purpose to obscure the moment of the loading of the card into the wallet. I am sure others must have hit upon this as well because it is such an obvious thought, so I claim no originality. See it as a reminder of something important (which not only applies to the Card to Wallet trick).
The basic idea here is to get the spectators used to the action of the hand reaching into the jacket for the wallet. Once they are conditioned to this action, and see that nothing unusual or suspicious happens, they will miss the moment of the actual loading (or, in the worst case, ignore it).
In theory, if you do this movement two times, and they see that nothing suspicious happens, then they won’t notice the third time. Again the magical three.
Reconstruct your routine to make this possible. Integrate some (motivated) reason that allows you to reach into the pocket, remove the wallet, and then remove something from the portfolio which has some meaning in the routine’s context. This could be a bill, a slip of paper (with something written on it which is part of the presentation), or, in fact, anything that would serve the routine. The handling is this: you reach into the pocket, remove the wallet, open it, and take out a slip of paper with the other hand. While the paper is unfolded and shown around, the hand holding the wallet closes it and puts it back into the pocket.
Do this another time with some different object in the wallet (or return the slip taken out beforehand). The third time, you have the card palmed and reach with that hand for the wallet. Load the card, remove the portfolio and then proceed to the revelation of the card in the sealed envelope inside the zip compartment of the wallet, etc.
This conditioning, as innocent as it may seem, is a reliable strategy that covers the moment.